Greg writes –
This site provides a complete design for a nixie tube clock. In this site you will find the schematic, layout, source code, specifications, bill of materials and an enclosure example for my clock design. I have worked on my nixie tube clock design for more than 2 years. The material provided is my design and is thus copyright; I provide it with the intention of sharing my enthusiasm and enjoyment of designing and building a nixie tube clock.
sputnixie.com – Link.
(Update, not open sourced – still cool).